A Sherlock coat is a long, slender-cut pea coat or cape coat made of wool or tweed. Specifically, in the 2010 BBC drama "Sherlock," Benedict Cumberbatch wore a Belstaff "Milford" coat.
Pea coat has become a blanket term for many types of coats, although the original design has changed little since it was first mentioned in an American newspaper during the 1720s. Originally for sailors or naval use, the short coats were worn by lower-ranking individuals, while a longer version, called the bridge coat, was worn exclusively by officers. It is believed that the name "pea" comes from the name of the cloth used, though experts debate whether it is of Dutch or American origin.